1. Field of the Invention
The present invention relates to a polarization plate and a liquid crystal display.
2. Description of the Related Art
A liquid crystal display is a space-saving image display with small power consumption, and its application is widening every year. In the past, liquid crystal displays had a serious defect of a large viewing angle dependency of a displayed image, but a wide viewing angle liquid crystal mode such as a VA mode or an IPS mode has been put into practical use, and accordingly, the demand of the liquid crystal displays is rapidly expanding even in a market requiring a high-quality image such as a television.
In response to the expansion of the application of liquid crystal displays, there has been a demand for a larger size and higher-quality texture of liquid crystal displays. In the peripheral portion of a screen, there is a portion corresponding to a frame, which is called a bezel, and the width of the bezel is becoming narrower to produce a higher-quality texture. The bezel plays a role of aesthetically completing display by hiding the edge section of a polarization plate, and in response to the decrease in the width of the bezel, there has been a demand for a high-level attachment accuracy between a liquid crystal cell and the polarization plate.
The polarization plate used for liquid crystal displays has a configuration in which, generally, transparent protective films are attached to the front and back sides of a polarizer made of a polyvinyl alcohol film or the like in which iodine or a dye is adsorbed and oriented. As the polarization plate protective film, a cellulose acylate-based polarization plate protective film represented by cellulose acetate has been widely used since the cellulose acylate-based polarization plate protective film has high transparency and is capable of easily ensuring adhesiveness to polyvinyl alcohol which is used for the polarizer. Generally, the adhesiveness is obtained by carrying out a saponification treatment on the protective film to impart hydrophilicity to the surface.
For the reasons of its relatively high water vapor transmission rate and its capability of easily ensuring the adhesiveness to polyvinyl alcohol through a saponification treatment, the cellulose acylate film has been used, but its relatively strong water-absorbing property has caused a problem of a likelihood of the occurrence of a uneven screen in a case in which the humidity dependency of retardation is great, and the cellulose acylate film is used for a long period of time.
JP2009-292869A discloses a polarization plate in which an acryl-based film is used on one side, and a cellulose acylate film is used on the other side as the protective films for the polarizer.
In addition, JP2008-529038A discloses a polarization plate in which a cycloolefin-based polymer film is used on one side, and a cellulose acylate film is used on the other side as the protective films for the polarizer.